Grinding tool



Sept. 25, 1928. 1,685,100

D. L. SPRAKER GRINDING TOOL Filed y 21, 1926 I INVENTOR.

i Jim m L. SPKHAE/f.

A TTORNEYi Patented Sept. 25, 1928.

UNITED STATES PATENT OFFICE DAVID L. SPRAKER, OF INDIANAPOLIS, INDIANA,ASSI GNOR TO SPEAKER MANUFAC- TUBING QQMIANY, OF INDIANAPOLIS, INDIANA,A CORPORATION.

GRINDING TOOL.

Application filed May 21,

This invention relates to a grinding tool and particularl) that type oftool adapted for grinding valves in internal combustion engines.

The principal feature of the invention resides in the mechanism forrotating first in one direction and then in another a grinding toolthrough continuous rotation of another member.

The full nature of the invention will be understood from theaccompanying drawings and the following description and claims:

In the drawings Fig. 1 is a central vertical section through the toolshowing the siiaft and handle in elevation. Fig. 2 is a front elevationthereof with the closure cap removed. Fig. 3 is a sectional view takenon line 33 of Fig. 2 and in the direction of the arrows.

In the drawings there is shown a grinding tool comprising a shaft havingthe usual grinding head 11 keyed to the free end thereof. said shaftbeing rotatably mounted in a housing 12 through the medium of a bearing13. Said housing 12 has a closure cap 14. Mounted on the housing thereis an upwardly extending handle 15 provided with a metal shell 16positioned centrally in the lower end thereof. which shell provides theupper hearing for the shaft and is rigidly secured to the upper portionof the casing. A ball bearing 17 is mounted intermediate the upper partof the shaft 10 and the top of the metal shell 16 so as to provide anend thrust hearing.

The pins 18 and 19 are secured to the shaft within the shell. the pin 18being positioned adjacent the low portion of the shell and the pin 19being positioned adiacent the upper portion of the shell. The pins arepositioned substantially equi-distantfrom the center of the shell butare offset angularly with respect to each other. that is. lie indifferent radial planes. The shaft 10 is rotated through the medium ofthe respective pins 18 and 19 as will be hereinafter described.

Extending rearwardly from the center of the housing 12 there is abearing shell 21 in which is mounted a rotating shaft 22 operatedthrough a lever 23 having a handle 24. Interiorly of the shell there isa starwhcel 25 which is mounted for rotation with 1926. Serial No.110,681.

shaft 22. The star-wheel is provided with three radially extending camfingers 26 which are offset from the plane of the wheel toward the pinsand shaft 10. The radial fingers are of such length and so arranged asto mesh alternately with the pins 18 and 19.

The shaft 10 carries the pin 28 which secures said shaft inpredetermined position within the housing through the assistance ofanother pin 29 thereby positioning pins 18 and 19 substantiallyequi-distant from the center of the star-wheel or shaft 22. Pin 2.) 1S111?1l17.(l for an additional purpose. towit. it alternately engages thestop faces 30 of an arcuate stop 31 positioned adjacent the pin 29. andherein shown formed integral with the sleeve bearing 13.

In operation. the tool is held in position under pressure through themedium of handle 15. while the handle 21 is rotatable constantly in agiven direction. Rotation of the handle 24 causes a. like rotation ofthe star-wheel 25. lVhen one of the fingers or cams 26 of the star-wheelis in engagement with one of the pins 18 or 1!) the other pin will beout of engagement therewith. Lilo. wise. as will be clearly observed.the starwheel being rotated in its given direction. the pins 18 and 19will be alternately ro tated in opposite directions by reason of theopposing direction of movement of the fingers 26 when in engagementtherewith. The alternate engagement of the pins 18 and 19 willaccordingly cause the grinding tool to rotate alternately. first in onedirection and then in the other. By reason of the wide central anglebetween the fingers 26. engagement of a finger or cam 26 with pin 19will cease and the finger be disengaged before another finger engagespin 18. thus preventing interlocking of the tool by reason of thesimultaneous engagement of the two pins.

The invention claimed is:

1. A grinding tool including a rotatable shaft. a pair of pins on saidshaft positioned in different radial planes and in different parallelplanes transverse to the shaft, triangular star-wheel having a pluralityof radial extending fingers spaced apart. said fingers being adapted toengage first with one pin and then with the other for rotating said toolin opposite directions. said fingers being cqui-(listant from the axisof the starwheel and the latter being between said parallel planes.

2. A grinding tool including a rotatable shaft, but a pair of pins onsaid shaft, means for engaging first one pin and then the other formoving the same in opposite directions,

and means for limiting the oscillatory movement of the pin supportingshaft for insuring engageable positioning of the pins.

In Witness whereof, I have hereunto ailixerl my signature.

DAVID L. SPEAKER.

